Creator: Unrevealed (presumably whoever created and/or led the Death's Heads that arrived on Sakaar via the Great Portal)

User/Possessors: Father Emperor (Angmo the First), Imperial Guard of Sakaar, Red King (Angmo-Asan);
formerly the Death's Head Warguard

First Appearance: Incredible Hulk III#94 (June, 2006)

Powers/Abilities/Functions: While their power
source, nature, and destructive potential are not clearly described,
they are highly destructive weapons, capable of harming (but not
incapacitating) even an enraged Hulk.

They were usually dropped from
Imperial Dreadnoughts, which typically were stocked with eight
Deathfire Bombs.

They could be outfitted with chemical and biological warheads for maximum damage

History:
(Planet Hulk: Gladiator Guidebook#1: Imperial
Technology: Imperial Dreadnought (fb) - BTS) <536 post> - The Deathfire Bombs were
first discovered aboard the Death's Head flagship that arrived on
Sakaar via the Great Portal, presumably after the ship had been brought to Okini.

(Planet Hulk: Gladiator Guidebook#1: Sakaar: Geography: The
Wastelands (fb) - BTS / Planet Hulk: Gladiator Guidebook#1: The Imperials: The
Emperor) <540 Post>
- The Father Emperor, Angmo the First, ordered the Death's Head
Warguard to use their ship to attack the Spike-controlled Capital City
Umegus with Deathfire Bombs outfitted with biological warheads.

Although the
attack led to the Spike's ultimate defeat and ended the decades-long war, it
also permanently destroyed the surrounding environment, transforming the
beautiful land of Umegus into what would become known as the Wastelands. All that remained
of the former capital city and its province was a desolate, 400-mile-wide
circular blast radius surrounding the point where the Deathfire Bombs struck.

(Incredible
Hulk III#94) - When the Hulk's gladiatorial team -- Hiroim the Shamed of the Shadow People, No-Name of
the Brood, Hulk (Bruce Banner) of Earth, Elloe Kaifi of the Sakaaran
Imperials, Korg of the Kronans, Miek of the Sakaarian native, and Lavin Skee of the Sakaaran Imperials -- returned to the Great
Arena, the Red King had an Imperial dreadnought drop a deathfire bomb
on the gladiators, but the Hulk leapt into the air and intercepted the
bomb, sparing the other gladiators from the brunt of the explosion,
although Lavin Skee lost an arm and perished in the subsequent battle.

(Incredible
Hulk III#94 - BTS) - The announcer/commentator/etc. was shocked,
exclaiming that it was "...unbelievable. That was a precision Deathfire
bomb, detonated in the middle of the Great Arena in the center of Crown
City...against gladiators armed only with their shields and swords.
That was a gross violation of the rules. I've never...never seen..."

And a pair of Imperial Guardsmen relieved the announcer of his microphone and then took him away...

(Incredible
Hulk III#94 - BTS) - Having survived the explosion, the Hulk led his
allies to victory, and the survivors -- Hiroim, No-Name, Hulk, Elloe
Kaifi, Korg, and Miek -- united as (the) Warbound.

(Planet Hulk: Gladiator Guidebook#1: Imperial
Technology: Imperial Dreadnought (fb) - BTS) - The Emperor's advisors
assured the public that the bombing raid was the work of rogue
Fillian-sympathizers within the Imperial Guard.